The field of the invention is devices for facilitating the secure attachment of plumbing fixtures to concrete block and poured concrete walls. The invention relates more particularly to the mounting of plumbing fixtures in prisons, mental institutions and other locations where it is essential that the fixtures be secured in such a manner that it is virtually impossible to remove them from the wall. It is also important in such environments that the mounting device not provide any means of escape and also that it provide a highly fire retardant barrier.
In the past a common method of mounting plumbing fixtures was to cut holes through a concrete block or concrete wall and pass the pipes and bolt the fixtures through such holes. Such a method was of course very time consuming and thus expensive. A better method of mounting such fixtures is shown in U.S. Pat. No. 3,701,172 (McClenahan). It often occurred that when concrete was poured against the inner face of the plate that the pipes which were held to the plate were knocked out of line therby providing an imperfect opening.
A further improvement in the field is disclosed in U.S. Pat. No. 3,942,201 (Morris et al.). This wall sleeve provided the necessary strength but was not suitable for fire rated walls because of its open interior.